This patch adds missing `norecurse` attrs to funcs that only call intrinsics with `nocallback` attrs.
Fixes the regression found in https://github.com/dtcxzyw/llvm-opt-benchmark/pull/45#discussion_r1436148743.
The function loses `norecurse` attr because it calls `@llvm.fabs.f64`, which is not marked as `norecurse`.
Since `norecurse` is not a default attribute of intrinsics and it is
ambiguous for intrinsics, I decided to use the existing `callback`
attributes.
> nocallback
This attribute indicates that the function is only allowed to jump back
into caller’s module by a return or an exception, and is not allowed to
jump back by invoking a callback function, a direct, possibly
transitive, external function call, use of longjmp, or other means. It
is a compiler hint that is used at module level to improve dataflow
analysis, dropped during linking, and has no effect on functions defined
in the current module.
See also https://llvm.org/docs/LangRef.html#function-attributes.
Fixes#68270
The function attribute analysis handles many instructions, like
addrspacecast, which do not themselves read or write memory but which
transform pointers into other values in the same alias set.
There are intrinsic functions, such as ptrmask or the AMDGPU-specific
make.buffer.rsrc, which also preserve membership in alias sets without
capturing. This commit adds the addrspacecast-like behavior to these
calls.
